Defendant Megan Huntsman, 39, is accused of killing the babies between 1996 and 2006, before Utah law was changed in 2007 to make murder a capital offense if a victim was younger than 14, Utah County Attorney Jeff Buhman said outside court after a hearing in the case.

Until the law was passed, killing a child was not considered one of the aggravating factors that can make someone eligible for the death penalty, he said.

Such factors also include the victim being a police officer, the killing occurring while another crime, such as rape, was committed, or if the defendant has already been convicted of another murder. Killing more than one person also is considered a capital offense but only if they die in the same incident.

Authorities say Huntsman was the mother of the babies and they were awaiting DNA testing to confirm that along with the sex of the children. Their causes of death also remain uncertain.

No labs in Utah can analyze the type of DNA that has been taken from the small corpses, so the FBI has been brought in to help, police said.

The bodies of the infants were found on April 12 in boxes in Huntsman's garage in Pleasant Grove. A seventh infant found in the garage is believed to have been stillborn.